Friday, December 22, 2006

Looking for ways to fill up your Christmas holiday?

Then why not heed these shameless plugs for my friends? John Whitfield’s book In The Beat of a Heart is a fabulous read – one of the best science books of 2006, though it’s not received the UK push it deserves. If this doesn’t get shortlisted for next year’s Aventis Prize, there’s no justice. It explains the notion of metabolic scaling in biology – the idea that one can develop a unified view of life by considering the way energy requirements depend on size. Like Nick Lane’s Power, Sex, Suicide, it’s a timely reminder that there’s more to life than genes.

And if you’re in the Lincoln area, pay a visit to Lindsay Seers’ exhibition The Truth Was Always There, which explores connections between magic and alchemy, Lincoln cathedral, Robert Grosseteste, Temple Bruer and John Dee. This is part of an ongoing project by Lindsay, comprising five ‘biographical’ films that document a strange past and an obsession with becoming a human camera. There’s a forthcoming book, called (I think) Human Camera, that records these films and narratives. Yes, I admit that I’m a contributor – but that’s because I think it is a wonderful project. The exhibition runs until late January.

[This is the pre-edited version of my Crucible column for the February issue of Chemistry World.]

Life is pretty simple, when you come down to it. It’s a matter of shovelling stuff from one side of a wall to the other – the ‘stuff’ being hydrogen ions, and the wall a cell membrane. The biochemistry that follows from this is fearsome, but at root life is driven by piling up hydrogen ions and then letting them flow, like water released from a dam.

This imbalance of protons across a membrane creates a so-called protonmotive force. It is generated by proton pumps: proteins that can actively move protons ‘uphill, against a concentration gradient. They need energy to do that, and in the light-harvesting chloroplasts of plants that comes ultimately from sunlight, which sets an electron jumping between molecules. In our mitochondria the energy is generated by reactions that break down carbohydrates. In either case, the protonmotive force is used to power the enzyme ATP synthase, which rotates like a water wheel as it lets protons flow through, producing energy-rich ATP in the process.

So if that’s life in a nutshell, these proton pumps clearly need to be efficient and smooth-running pieces of molecular machinery. Even so, the ingenuity life displays in conducting and controlling the movement of protons is breathtaking.

That life exists in water is a boon from the outset – because one of the things water does that other liquids cannot is transport protons rapidly. The hydrogen ion travels faster than other small cations in water by hopping along hydrogen-bonded chains of water molecules: rather like a Newton’s cradle, a proton hits one end of the chain and almost at once (figuratively speaking) another proton pops off the other end. This hopping, called the Grotthuss mechanism after the nineteenth-century German scientist who proposed the basic idea, is exploited by biomolecules to shift protons. Some proteins, such as the light-powered bacterial proton pump bacteriorhodopsin and some cytochromes, are threaded by ‘water wires’, strings of water molecules that act as proton-conducting pathways.

A water wire also winds through the membrane protein aquaporin, which transports water across cell walls. But for aquaporin, letting protons through could be disastrous, as it would disrupt the delicate balance of pH and charge across the membrane. So it has to achieve the seemingly impossible feat of transporting water but not hydrogen ions. How it does so is still not fully clear, but one idea is that the water wire contains a defect: hydrogen-bonding to the amino-acid residues within the pore forces two waters in the chain to sit ‘back to back’, so that a proton can’t jump between them.

That would be an extraordinarily delicate feat of molecular manipulation. But it is possibly trumped by the latest revelation about why proton pumping works so well. Magnus Brändén of Stockholm University and his colleagues (Proc. Natl Acad. Sci. USA, doi:10.1073/pnas.0605909103) say that there are, in effect, little proton circuits written onto the surfaces of cell membranes that help guide protons from a transporter – a pump protein – to molecules that exploit the protonmotive force, such as ATP synthase. The image, then, is not that of a pump spouting out protons into the cytoplasm, where some gradually drift over to where they’re needed; instead, the protons pop out of the pump’s mouth and stick to the membrane before proceeding to hop across it. That way, fewer get lost.

In effect, then, the membrane lipids act as proton-collecting antennas – rather as accessory pigments serve as light-harvesting antennas to shunt light energy onto the photosynthetic reaction centre in photosynthesis.

This idea has been mooted for years, but Brändén and colleagues have pinned it down by looking at the protonation of a single fluorescein dye molecule embedded in the wall of liposomes (closed, cell-like assemblies of lipids). Protonation changes the dye’s fluorescence, and so fluctuations in its brightness can be related to the rate of proton exchange with the surroundings. The researchers show that this happens at a faster rate than would be expected if protons were just being exchanged with the water – so long as the lipid head groups can themselves be protonated. The lipids gather protons and pass them around.

It’s a reminder that molecular biology isn’t just about the cleverness of proteins and nucleic acids. Even the molecules often assumed to be just part of the background or the scaffolding, such as lipids and water, may have inventive roles to play.

Thursday, December 21, 2006

Mining the moon for all it’s worth

It's one of the curious characteristics of space exploration that the usual stringent hurdles for science news stories are nowhere to be seen. Whereas normally science reporters, enthusing breathlessly about new insights into, say, the origin of the universe, face an editor's dismissive "why do we care?", with space stories it is enough that someone did something or other up in space – hit a gold ball, say, or flew a shuttle mission without blowing up. True, if the story involves an unmanned spacecraft doing something like landing on a comet, then there might be some sales work to be done. But if there's a human inside, it doesn't much matter what he's up to – just stick it on the page.

That principle even extends to stuff that hasn't actually been done, but "will" be. We're going to send people to Mars! We're going to build a moon base! Yes, it's true that we've not even managed to finish off a useless piece of manned space junk floating inanely in Earth orbit, but look, we've learnt from our mistakes. (What we've learnt, it seems, is simply to make the claims bolder.) When something is going to be done in space, all critical faculties vanish. We're going to grow crystals there, or plants – and no matter whether that's really going to tell us anything worthwhile. And now the latest fad for which the media seems determined to fall hook, line and sinker is mining the moon for helium-3.

Helium-3, you see, is a wonderful clean fuel that will power our planet through nuclear fusion. Just a shuttle-load will power the USA for a year. And it's just waiting up there in the lunar soil for us to go and collect it.

Well actually, it isn't – we'd have to strip-mine vast areas of the moon to get at it. And while discussions of remote oil resources on Earth routinely have to run the gauntlet of hard-headed economical cost-benefit analysis, no one seems to care very much whether there is any justification for thinking that sending trucks to the moon to pick up this 'fuel' is really going to save anyone any money. All you have to do is talk about lunar helium-3 as a "cash crop".

And on top of that, there's the small difficulty that no one has ever produced energy from nuclear fusion in a commercially viable and sustainable way, and that even the most optimistic estimates put that goal 50 years distant. There's a good chance that it might not happen before 2100 (although making technological projections that far ahead is a bit pointless anyway).

The point is, of course, that these bogus utilitarian rationales are routinely trotted out in defence of a programme of human space exploration that is at root ideological. It's fine to believe that there is an intrinsic value in sending humans to other worlds (I happen to disagree, at least in the present state of affairs in space travel); but let's at least be honest about it. The magic word "resources" was invoked the last time I questioned the value of manned spaceflight (see here and here). But as I'd expected, when it came down to it what that meant was stuff like silicon – as though we are currently facing a silicon shortage here on our rocky planet.

So please – no more helium-3 as the justification for a moon base. That’s truly grasping at straws.

Monday, December 18, 2006

[This is a review of a book on the zoological art of Ernst Haeckel, to be published in Nature.]

Visions of Nature: The Art and Science of Ernst HaeckelOlaf BreidbachPrestel, Munich, 2006

When Nature’s millennial issue of 1900 listed the most important scientists of that age, there was only one German biologist among them: Ernst Haeckel, professor of zoology at the University of Jena. Reckoned to have been instrumental to the introduction of Darwinism in Germany, and responsible now for inspiring generations of scientists with his stunning drawings of the natural world, Haeckel still retains a claim to such recognition. He is perhaps most widely known now as the author and illustrator of Art Forms in Nature, a series of plates published between 1899 and 1904 that showed the marvellous forms and symmetries of creatures ranging from radiolarians to antelopes.

But few scientists of his time are more complicated. He was the archetypal German Romantic, who toyed with the idea of becoming a landscape painter, venerated Goethe, and was prone to a kind of Hegelian historical determinism that sat uncomfortably with Darwin’s pragmatic rule of contingency. Haeckel’s view of evolution was a search for order, systematization and hierarchy that would reveal far more logic and purpose in life than a mere struggle for survival. His most famous scientific theory, the so-called biogenetic law which argued that organisms retread evolutionary history as they develop from an egg (‘ontogeny recapitulates phylogeny’), was an attempt to extract such a unifying scheme from the natural world.

It can be argued that this kind of visionary mindset, when it creates strong preconceptions about how the world ought to be, does not serve science well. Haeckel supplies a case study in the collision between Romanticism and science, and that tension is played out in his illustrative work. Olaf Breidbach’s text to this lovingly produced volume never really gets to grips with that. It has a curiously nineteenth-century flavour itself, declining to grapple with the difficult aspects of Haeckel’s life and work.

Here, for instance, is a proposition: Ernst Haeckel’s influence on fin-du-siècle German culture was pernicious in its promotion of a ‘scientific’ racist ideology that fed directly into Nazism. That case has been made (by historian Daniel Gasman in particular), and while it can be debated, Breidbach goes no further than to admit that Haeckel became a ‘biological chauvinist’ during the First World War, and that ‘sometimes the tone of his writing was overtly racist.’ Breidbach admits that this is not a biography as such, but an examination of Haeckel’s visual heritage. Yet one could argue that Haeckel’s dark side was as much a natural consequence of his world view as was Art Forms in Nature.

The claim that Haeckel doctored images in order to make them fit with a preconceived notion of how biology works is harder to ignore in this context. Even in his own time he was accused of that (particularly by his rival Wilhelm His), and to my eye the evidence (see Nature410, 144; 2001 and Science277, 1435; 1997) looks pretty strong. But Breidbach skates over this issue, alluding to the allegations only to suggest that the illustrations ‘instructed the reader how to interpret the shapes of nature properly’. Well, indeed.

On the whole, though, Breidbach simply explains Haeckel’s reliance on image without assessing it. Haeckel’s extraordinary drawings were not made to support his arguments about evolution and morphogenesis; rather, they were the arguments themselves. He believed that these truths should be apparent not by analysing the images but simply by looking at them. ‘Seeing was understanding’, as Breidbach says. If that’s so, it places an immense burden of responsibility on the veracity of the images.

This is the nub of the matter. Breidbach suggests that Haeckel’s drawings are schematic and that, like any illustrator, Haeckel prepared them to emphasize what we are meant to see. But of course this means ‘what Haeckel has decided we should see’. Quite aside from whether he hid nascent appendages that challenged his biogenetic law, consider what this implies for the plates of Art Forms in Nature. They are some of the most beautiful illustrations ever made in natural history – but it seems clear now that Haeckel idealized, abstracted and arranged the elements in such a way that their symmetry and order was exaggerated. They are pictures of Platonic creatures, the ideal forms that Haeckel intuited as he gazed into his microscope. Their very beauty betrays them. They are, as Breidbach says (but seemingly without critical intent), ‘nature properly organized.’ In this way ‘the labour of the analyst was replaced by the fascination of the image’. Absolutely – for ‘fascinate’ used to mean ‘bewitch’.

It is not as if Haeckel did not have the alternative of photography – for microphotography was used as early as the 1850s. Breidbach recapitulates the arguments against an over-reliance on the veracity of photography (these ideas have been much discussed by cultural critics such as Vilém Flusser), pointing out that what one sees is determined by the technology. That is true, and it is apt to give photography a false authority. But are hand-drawn images really any better – let alone those rendered with such apparent skill and realism that their schematic nature is disguised? Indeed, Haeckel felt compelled in 1913 to publish Nature as an Artist, a series of photographs of his subjects which, he said, demonstrates that ‘there can be no talk of reconstruction, touching up, schematisation or indeed forgery’ in his drawings of the same. It was a remarkable work in its own right, but leaves us wondering why Haeckel did not use photos in the first place.

Another danger of such imagery is that it is prone to reflect the artistic styles of the day. Haeckel’s drawings fed into the florid, nature-inspired designs of the Art Nouveau and Jugendstil schools – but he was more influenced than influence. His medusae look like William Morris prints precisely because they have had that visual aesthetic imprinted on them. Breidbach says that for Haeckel, as for Goethe, ‘aesthetics is the foundation of his view of nature.’ But is that a good thing? As Ernst Gombrich has pointed out, artistic styles create unconscious biases and errors: when Gombrich speaks of the artist who ‘begins not with his visual impression but with his idea or concept’, it might as well be Haeckel he is talking of. And what happens when the cultural aesthetic moves on – does nature have to follow suit? Breidbach points out that, by using the visual language of his age, Haeckel helped to make science accessible to the public. But 20 years later, modernism had rendered his arabesque style old-fashioned.

As director of the Ernst Haeckel Museum at Jena, Breidbach has unequalled access to Haeckel’s notes and sketchbooks, and he makes good use of them. But perhaps for that very reason he felt unable to dig too deeply into the problematic areas his subject raises. (Haeckel is clearly still very much a legend at Jena, where his brain was cast in silver.) So although this is undoubtedly a gorgeous book, and the questions it raises are fascinating, I can’t help feeling that it represents an opportunity missed.

Thursday, December 14, 2006

Tainted by association?[This is the pre-edited version of my latest muse column for news@nature.]

Richard Doll's links with industry are disconcerting but hardly scandalous. And they don't make him a villain.

Few things will polarize opinion like the defamation of a recently deceased and revered figure. So the tone of the debate (here and here and here and here) that has followed the accusation that Sir Richard Doll, the British epidemiologist credited with identifying the link between smoking and lung cancer in the 1950s, compromised the integrity of his research by receiving consultancy payments from the chemicals industry, should surprise no one.

On the one hand, the disclosure of Doll's contracts with the likes of Monsanto and Dow Chemicals have provoked howls of outrage and accusations that his studies of purported links between the companies' products and cancer were nothing less than a cover-up. Much of this is crude conspiracy-theorizing; but there are also more weighty critics. Andrew Watterson, a professor of occupational and environmental health at the University of Stirling in Scotland, has said that "Doll's work… has limited the capacity of the UK over decades to take action on occupational and environmental carcinogens as quickly as it should have… His lack of transparency on and financial relationship with companies have seriously damaged the credibility of aspects of his research."

On the other hand, voices that will be no doubt dismissed by Doll's attackers as those of the 'establishment' have risen to defend his reputation. An editorial in the Times calls the charges "a cheap shot" made by "grave robbers". This, the newspaper intones gravely, is "a sad act of character assassination by people who should know better." Several leading UK scientists have written to the Times saying that "we feel it is our duty to defend Sir Richard's reputation and to recognise his extraordinary contribution to global health."

The situation is perhaps best exemplified by a leader headline in the Observer newspaper: "Richard Doll was a hero, not a villain." All of which brings to mind the comment of Brecht's Galileo: "unhappy is the land that needs a hero."

Unhappy we are indeed, if we cannot accommodate in our pantheons the complexities of real people. And while the collaborations of academe and industry certainly create tensions and problems, it achieves nothing to pretend that they ought not to exist.

Doll's consultancy work is not immune to criticism even by the standards of his time. But the suggestion that his research is invalidated, and his character besmirched, by such conflicts of interest (as they would now certainly be regarded) is one that smells of piety rather than an evaluation of the facts.

Here, then, is the case for the prosecution. Doll proclaimed that Monsanto's Agent Orange posed no carcinogenic hazard while receiving consultancy fees of $1000-1500 a day from the company for nearly 30 years. He compiled a review on behalf of ICA, Dow Chemicals and the Chemical Manufacturers' Association in their defence against claims of cancer induced in workers by exposure to vinyl chloride, for which he was paid £15,000. (Monsanto was also a big producer of vinyl chloride). And he argued that there was little basis for the idea that asbestos is a major health risk, while pursuing a long-term consultancy relationship with the UK's leading asbestos manufacturer Turner & Newall, which later donated £50,000 to set up Green College in Oxford, a medical school of which Doll was a founder and the first warden.

All of this would indict any researcher today who failed to declare such conflicts of interest. Doll was in fact rather inconsistent about such declarations – he made no secret of some of his links to industry, but the Monsanto connection was not disclosed until a court case over vinyl chloride in 2000. In any event, until the 1980s there was no expectation that academics should make this sort of paid work public, and so no reason to expect Doll to have been systematic about doing so.

That is one of the main lines of defence for Doll's supporters: it is absurd to judge him by today's standards, a notorious way of vilifying historical figures and events. It's a fair point, although we have to remember that we're talking here about the 1980s, not the nineteenth century. It doesn't take a great deal of insight to see that being paid by a company while assessing their products is not ideal.

Yet there is no obvious reason to regard this as venal or cynical on Doll's part. Using contract money to help set up a college does not seem particularly blameworthy. Doll donated other fees to charities such as the Medical Foundation for the Victims of Torture.

He gives every impression of being a man conducting his business in an environment that had not thought very hard about the proprieties of industrial research contracts. If he did not think too hard about it either, that does not make him a villain.

And he seems very much a man who knew his own mind. Overcoming industry's resistance to the link between smoking and cancer is hardly the act of someone in the pocket of corporations. Yet his scepticism about the effects of secondary smoking speaks of a man who was not turned into an ideologue by his conclusions.

On this count, we must remember that no evidence has been presented that Doll's conclusions were biased by his contracts. It's hard to see how that could be established either way; but certainly it is unfair to turn Doll into a yes-man bribed by industry.

Indeed, if anything, the affair has served to remind us how manipulative these industries could be. Peto says that Doll came under pressure (which he resisted) from the asbestos manufacturers not to publish any evidence of the harmful effects of their product. They claimed it would damage the national interest by undermining this important industry, and even threatened legal action. The Asbestosis Research Council, founded by Turner & Newall and others in 1957, has been accused of suppressing evidence of the dangers of asbestos, for example by vetting and censoring research on the topic [1].

A curious aspect of this whole business, not mentioned at all in media reports, is that it is all yesterday's news anyway. Doll's links with industry were reported by British newspapers after being discussed in an article published online on 3 November by the American Journal of Industrial Medicine [2]. But the information in that article on Doll's connections with Monsanto, Dow, Turner & Newall and others had all been documented in 2002 by one of the authors, Martin Walker [3]. In that latter paper, Walker states that Doll "has never made any secret of the fact that he has been funded by industry for specific research projects."

Quite aside from demonstrating the media's ability to generate its own content, this fact is notable because the American Journal of Industrial Medicine paper aims not to denigrate Doll but to call for a tightening of policies governing disclosures of interest today. There's still plenty of work to be done (see here and here) in that respect. We should recognise the shortcomings of the past, and move on.

Monday, December 04, 2006

Looking for Turing’s fingerprints

Here is the pre-edited version of my Crucible column for the January 2007 issue of Chemistry World.There’s considerably more on this issue in the forthcoming reworking of my 1999 book The Self-Made Tapestry. OUP will publish this as a series of three books, probably beginning in late 2007.

How did the leopard get its spots? Recent research supports an idea first suggested by legendary code-breaker Alan Turing.

After another long time, what with standing half in the shade and half out of it, and what with the slippery-slidy shadows of the trees falling on them, the Giraffe grew blotchy, and the Zebra grew stripy, and the Eland and the Koodoo grew darker, with little wavy grey lines on their backs like bark on a tree trunk; and so, though you could hear them and smell them, you could very seldom see them, and then only when you knew precisely where to look.

Kipling’s Just So story of how the animals of Africa obtained their distinctive marking patterns is a fine example of Lamarckism – the inheritance of environmentally acquired characteristics, in this case via what seems to be a kind of tanning process imprinted with the shadows of trees. But the explanation that his contemporary biologists would have offered, invoking Darwinian adaptation (the markings being assumed to serve as camouflage), was arguably little more than a Just So story too. It explained why a marking pattern, once acquired, would spread and persist in a population, but it could say nothing about how such a pattern came to be, either in evolutionary terms or during the embryonic development of a particular zebra, giraffe or koodoo.

It seems clear that this is not merely a genetic painting-by-numbers: the markings on two animals of the same species are recognizably alike, but not identical. How do the melanin pigments of animal pelts get distributed across the embryonic epidermis in these characteristically blotchy ways?

The favoured explanation today invokes a mechanism proposed in 1952 by the British mathematician Alan Turing, two years before his suicide by cyanide. Turing is best known for his work on artificial intelligence and the concept of a programmable computer, and for his wartime code-cracking at Bletchley Park. But his paper ‘The chemical basis of morphogenesis’ was something else entirely. It was an attempt to explain how the development of a body plan kicks off.

The fundamental question is how a spherical ball of cells ends up as a shape in which different cells, tissues and appendages are assigned to different locations. How does the initial spherical symmetry get broken? Turing’s comment reminds one of the old joke about physicists over-simplifying biology: “a system which has spherical symmetry, and whose state is changing because of chemical reactions and diffusion, will remain spherically symmetrical for ever… It certainly cannot result in an organism such as a horse, which is not spherically symmetrical.”

Turing proposed a set of differential equations which explained how molecules determining cell fates, called morphogens, might diffuse through a spherical body and induce (bio)chemical processes. Such a scheme is now called a reaction-diffusion system. The patterning results from competition between an autocatalytic reaction, which amplifies random chemical inhomogeneities, and diffusion, which smoothes them out. Turing’s calculations performed by hand (his notion of a digital computer was then barely realized) showed that patchiness could emerge. But it wasn’t until 1972 that Hans Meinhardt and Alfred Gierer in Germany clarified the essential ingredients of Turing’s model. The chemical patterns arise in the presence of an autocatalytic ‘activator’ molecule, and an inhibitor molecule that suppresses the activator. If the inhibitor diffuses more rapidly than the activator, then the concentration of activator is enhanced over short distances but lowered by the inhibitor over longer distances. This gives rise to islands of activator surrounded by regions where it is suppressed.

Calculations showed that this ‘activator-inhibitor’ mechanism could create orderly patterns of spots and stripes, more or less equally sized and equidistant. That brought to mind the leopard’s spots and the zebra’s stripes. But is such a system anything more than a pretty mathematical fiction? That wasn’t clear until 1990, when a team led by Patrick De Kepper at the University of Bordeaux identified the first chemical Turing pattern, using a reaction that, when well mixed, oscillated between yellow and blue states. This was closely related to the Belousov-Zhabotinsky (BZ) reaction, which was known since the 1960s to generate travelling chemical waves. The BZ reaction is a reaction-diffusion system, but does not itself produce stationary Turing patterns, because the relative diffusion rates of the reactants don’t fit Turing’s model.

Are patterns in the living world really made this way? Theoretical activator-inhibitor systems have now been able to provide very convincing mimics of a wide range of animal markings, from the reticulated mesh of the giraffe’s pelt to the crescent-shaped rosettes of the leopard and jaguar, the spots of the ladybird and the stripes of the zebrafish. All this looks plausible enough, but the clinching proof – the identification of diffusing morphogens responsible for pigmentation – has yet to be obtained.

There does now seem to be good evidence that chemical morphogens of the sort Turing envisaged act in biological development. Several proteins belonging to the class called transforming growth factor b proteins seem to act this way in fly and vertebrate morphogenesis, signalling the developmental fate of cells as they diffuse through the embryo.

But does anything like Turing’s mechanism act to shape embryos beyond the question of marking patterns, as Turing suggested? In general, embryogenesis seems more complex than that, operating under close genetic control. However, Thomas Schlake and colleagues at the Max Planck Institute of Immunobiology in Freiburg have very recently discovered that there is at least one other biological patterning process that apparently uses the activator-inhibitor mechanism. They have found that the follicles of mouse hair are positioned in the epidermis by the protein products of two classes of gene, called WNT and DKK. The former appears to take the role of activator, inducing follicle formation, while several variants of DKK proteins act as inhibitors1.

Hair and feather positioning has long been suspected as an example of a Turing pattern – the equidistant, roughly hexagonally packed patterns are just what would be expected. Schlake and colleagues have made that case by looking at how over-expression of WNT and DKK alters the follicle patterns on mutant mice, showing that these match the predictions based on an activator-inhibitor model. It is probably the best reason yet to think that Turing’s intuition was sound.

Friday, November 24, 2006

[This is the pre-edited text of my latest muse for Nature, which relates to a paper published in the 16 November issue on health and safety issues in nanotechnology.]

Discussions about the risk of emerging technologies must acknowledge that their major impacts have rarely been spotted in advance.

In today's issue of Nature, an international team of scientists presents a five-point scheme for "the safe handling of nanotechnology"[1]. "If the global research community can rise to the challenges we have set", they say, "then we can surely look forward to the advent of safe nanotechnologies".

The five targets that the team sets for addressing potential health risks of nanotechnologies are excellent ones, involving the assessment of toxicities, prediction of impacts on the environment, and establishment of a general strategy for risk-focused research. In particular, the goals are aimed at determining the risks of engineered nanoparticles – how they might enter and move in the environment, to what extent humans might be exposed, and what the consequences of that will be. We need to know all these things with some urgency.

But what is a "safe technology"? According to this criterion, manufacturing nuclear warheads would be "safe" if no human was exposed to dangerous levels of radiation in the process that leads from centrifuge to silo.

To be fair, no one denies that a technology's 'safety' depends on how it is used. The proposals for mapping nanotech's risks are clearly aimed at a very specific aspect of the overall equation, concerned only with the fundamental issues of whether (and how much) exposure to nanotechnological products is bad for our health. But it highlights the curious circumstance that new technologies now seem required to carry out a risk assessment at their inception, ideally in parallel with public consultation and engagement to decide what should and shouldn't be permitted.

There is no harm in that. And there's plenty of scope for being creative about it. Some of the broader ethical issues associated with nanotech, for example, are being explored in the US through a series of public seminars organized by the public-education company ICAN Productions. Funded by the US National Science Foundation, ICAN is creating three one-hour seminars in which participants, including scientists, business leaders and members of the public, explore scenarios that illuminate plausible impacts of nanotech on daily life. The results will be presented on US television by Oregon Public Broadcasting in spring of 2007.

Yet history must leave us with little confidence that either research programs or public debates will anticipate all, or even the major, social impacts of a new technology. We smile now at how anyone believed that road safety could be addressed by having every automobile preceded by a man waving a red flag. In those early days, the pollution caused by cars was barely on the agenda, while the notion that this might affect global climate would have seemed positively bizarre.

Of course, it is something of a cliché now to say that neither the internal combustion engine nor smoking would ever have been permitted if we knew then what we know now about their dangers. But the point is that we never do – it is hard to identify any important technology for which the biggest risks have been clear in advance.

And even if some of them are, scientists generally lose the ability to do anything about it once the technology reacts with society. Nuclear proliferation was forecast and feared by many of the Manhattan Project physicists, but politicians and generals treated their proposals for avoiding it with contempt (give away secrets to the Russians, indeed!). It took no deep understanding of evolution to foresee the emergence of antibiotic-resistant bacteria, but that didn't prevent profligate over-prescription of the drugs. The dangers of global warming have been known since at least the 1980s, and… well, say no more.

In the case of nanotechnology, there have been discussions of, for example, its likelihood of increasing the gap between rich and poor nations, its impacts on surveillance and privacy, and the social effects of nanotech-enhanced longevity. These are all noble attempts to look beyond the pure science, but it's not at all clear that they will turn out to be the most relevant issues.

Part of the impetus for aiming to address the 'risks' of nanotech so early in the game comes from a fear that potentially valuable applications could be derailed by a public backlash like that which led to a rejection in Europe of genetically modified organisms – some (though by no means all) of which resulted from a general lack of information or understanding about the technology, as well as an arrogant assumption of consumer acquiescence.

The GMO experience has sensitized scientists to the need for early public engagement, and again that is surely a good thing. It's also encouraging to find scientists and even industries hurrying along governments to do more to support research into safety issues, and to draft regulations.

What they must avoid, however, is giving the impression that emerging technologies are like toys that can be 'made safe' before being handed to a separate entity called society to play with as it will. Technologies are one of the key drivers of social change, for better or worse. They simply do not exist in isolation of the society that generates them. Not only can we not foresee all their consequences, but some of those consequences aren't present even in principle until culture, sociology, economics and politics (not to mention faith) enter the arena.

Some technologies are no doubt intrinsically 'safer' or 'riskier' than others. But the more powerful they are, the less able we are to distinguish which is which, or to predict how that will play out in practice. Let's by all means look for obvious dangers at the outset – but scientists must also look for ways to become more engaged in the shaping of a technology as it unfolds, while dismantling the now-pervasive notion that all innovations must come with a 'risk-free' label.

Monday, November 20, 2006

Hooke: what came next?

I went to a nice talk by Lisa Jardine at the (peripatetic) Royal Institution last week, on the newly discovered notes of Robert Hooke. Lisa and her students have been studying this portfolio of notes taken by Hooke in his capacity as secretary of the Royal Society since they were rescued from auction and returned to the Royal Society earlier this year (see my earlier blog entry in May). She says that they have completely transformed her view of Hooke since writing his biography (The Curious Life of Robert Hooke, HarperCollins) in 2003. One of the hazards of being a historian, she pointed out, is that you can never be sure what may come to light and revise all your opinions, which have previously been presented to the world with such blithe authority. Well, that happens in science too, of course.

Lisa is now convinced that Hooke himself, not Newton, was his worst enemy: he was a terrible record keeper, and never finished anything. For all his protestations of priority over Huygens in regard to the invention of the spring-balance pocket watch, it seems that he may have sunk his claim himself. The new notes include a page taken from the private notes of Henry Oldenburg, written in 1670, in which Oldenburg relates how Hooke presented such a watch (Huygens’ version was patented in 1674), and then leaves a space for a description of the mechanism, apparently for Hooke himself to fill in the details. Hooke seems to have done this sketchily in pencil, but his words got worn away and he never amended them more permanently. So Oldenburg got no further in trying to transcribe them than a few lines before apparently giving up and crossing the whole lot out. But worst of all, Hooke seems to have filched the page from Oldenburg’s papers after the latter’s death, in the course of preparing his priority claim in obsessive detail – and then promptly left it buried in his own notes until it has surfaced now. So when Oldenburg’s papers were later checked to assess Hooke’s claim, there was no sign of this page!

I’m also interested to hear that the Hooke pages are shortly to be ‘conserved’ – which means that the book will be taken apart and each page placed inside plastic (Lisa says the pages are already literally falling apart beneath their fingers). So I’ll be one of the few ever to have touched the originals, and to have seen the book in its pristine form. Phew.

Wednesday, November 15, 2006

Economists as storytellers

Economist blogger Dave Iverson has written to me about my “tease” (his words, nice choice) in the Financial Times about neoclassical economics. Dave has previously commented in a way that I found insightful and fair on the exchanges and debates in the blogosphere, particularly those on Mark Thoma’s and Dave Altig’s sites. His latest post is another useful contribution, and here it is:

“Philip Ball's Financial Times' critique of economics, titled Baroque Fantasies of a Peculiar Science caused quite a stir recently in the economics blogs (particularly here here and here here.). But last week the bickering subsided with Dave Altig (macroblog) and Philip Ball seeming to have reached an accord.. At one point Altig said, "If you want, call economics an attempt to construct coherent stories about social phenomenon..." Sounds about right to me. We economists are indeed story tellers. Following this discussion, it seems clear that economists need to be much more open and honest about our assumptions and the linkages, such as they are and often are not to the real world of policy and action. No argument from me on that score. I've been arguing similarly for years.

“For more critique, see Steve Cohn's August 2002 Telling Other Stories: Heterodox Critiques of Neoclassical Micro Principles Texts, wherein Cohn attacks the "'rhetoric' of neoclassical theory, …critiquing many of the stories told, the metaphors used, the analogies drawn, and the framing language deployed."

“In addition, there have been many book-form critiques arguing that economists, particularly neoclassical economists have over-driven their headlights in much the same way that Bell argues. Here are six of my favorites (arranged by date of publication): J. de V. Graaff. Theoretical Welfare Economics. 1957 Guy Routh. The Origin of Economic Ideas. 1975 Mark Blaug. The Methodology of Economics: Or How Economists Explain. 1980 Robert L. Heilbroner. Behind the Veil of Economics: Essays in the Worldly Philosophy. 1988 Mark Sagoff. The Economy of the Earth: Philosophy, Law and the Environment. 1988 Andrew Bard Smookler. The Illusion of Choice: How the Market Economy Controls Our Destiny. 1993”

The Cohn paper is excellent – it says pretty much all of what I said in the FT article and much more, and in more depth, and frankly more persuasively. I particularly liked this, in relation to Paul Ormerod’s FT critique of how the textbooks tell the same old neoclassical story, despite what some of the practitioners are now doing to the contrary:

“We shouldn’t allow neoclassical economists to “run away” from their textbooks. The tracts educate well over a million students a year and lay the groundwork for much of educated opinion about economic issues. They should be defended or abandoned. In critiquing principles texts we should quote from the books themselves and if charged with attacking straw men, ask who is to blame: the textbook authors who built these scarecrows, or the photographers who took their picture?”

In any event, I offer the Cohn paper to those who say I’ve misrepresented the field (or have misused the word ‘neoclassical’). And I do so partly because Cohn seems to me to be very fair, acknowledging (in a way that I admit I could have done more explicitly) some of the ways in which modern economics has moved beyond the simplistic picture. This seems to me to be about dialogue rather than attack – which is absolutely what I’d like to see.

Tuesday, November 14, 2006

Was life inevitable?

Here’s the unexpurgated version of my latest story for news@nature. There’s a lot of really interesting back story here, which I hope to return to at some point. This is far and away some of the most interesting “origin of life” work I’ve seen for some time.

Life may be the ultimate in planetary stress relief, a new theory claims

The appearance of life on Earth seems to face so many obstacles that scientists often feel forced to regard it almost as miraculous. Now two scientists working at the Santa Fe Institute in New Mexico suggest that, on the contrary, it may have been inevitable.

They argue that life was the necessary consequence of the build-up of available energy on the early Earth, thanks to purely geological processes. They regard it as directly analogous to the way lightning relieves the build-up of electrical charge in thunderclouds.

In other words, say Harold Morowitz and Eric Smith in a preprint posted on the Santa Fe Institute archive [1], the geological environment "forced life into existence".

This view, the researchers say, implies not only that life had to emerge on the Earth, but that the same would happen on any similar planet. And they hope that ultimately it will be possible to predict the first steps in the origin of life based on the laws of physics and chemistry alone.

Their proposal is "instructive and inspiring", says Michael Russell, a specialist in the origin of life at the California Institute of Technology in Pasadena.

Morowitz and Smith admit that they don't yet have the theoretical tools to clinch their arguments, or to show what form this "inevitable life" must take. But they argue that it is likely to have used the same chemical processes that now drive our own metabolism – but in reverse.

They say that the young Earth would have been accumulating energy from geological processes much as a dam accumulates gravitational potential energy by piling up water. Sooner or later, something had to give.

One source of such energy would have been energy-rich compounds called polyphosphates, generated in volcanic processes. These are 'battery molecules', analogous to the compound ATP, the ubiquitous source of metabolic energy in living cells.

Another source would have been hydrogen molecules, which are likely to have been abundant in the early atmosphere even though they are almost absent today. Hydrogen would have been generated, for example, by reactions between seawater and dissolved iron.

Energy-releasing reactions between hydrogen and carbon dioxide (a volcanic gas) in the atmosphere can produce complex organic molecules, the precursors of living systems.

In our own metabolism, a series of biochemical reactions called the citric-acid cycle breaks down organic compounds from food into carbon dioxide. Horowitz and Smith say that the energy reservoirs of the young Earth could have driven a citric-acid cycle in reverse, spawning the building blocks of life while relaxing the 'energy pressure' of the environment. Eventually these processes will have become encapsulated in cells, which makes the 'energy-conducting' flows more efficient.

Life, agrees Russell is "a chemical system that drains and dissipates chemical energy." He has used similar ideas to argue that "life would emerge using the same pathways on any sunny, wet rocky planet" [2,3]. But he believes that the most likely place for it to occur was at miniature subsea volcanoes called hydrothermal vents, where the ingredients and conditions are just right for energy-harnessing chemical machinery to develop [4].

The biochemical processes of living organisms are highly organized. Scientists have long puzzled over how these 'ordered' systems can come spontaneously into being, when the Second Law of Thermodynamics suggests that the universe as a whole tends to generate increasing disorder.

The answer, broadly speaking, is that local clumps of order come at the expense of increasing the disorder in their environment. But Horowitz and Smith suggest a rationale for why such concentrations of order should happen in the first place. They draw on the idea, proposed in the 1980s by Rod Swenson of the University of Connecticut, that ordered states are much better 'lightning' conductors' for discharging excess energy.

Thus, they say, despite several major extinctions throughout geological time, when most of life on Earth was obliterated, life itself was never in danger of disappearing – because an Earth with life is always more stable than one without. They call this 'condensation' of life from the energy-rich environment a "collapse to life", which in their view is as inevitable as the appearance of snowflakes in cold, moist air.

Friday, November 10, 2006

No offence?

Well well, I hadn’t anticipated that I was lighting a fuse with my FT article on economics. There has been more follow-up in the FT itself – Paul Ormerod wrote a very nice Comment which was partly something of a response to some of the letters claiming that economics ain’t like that any more. Paul’s point is that yes, perhaps academic economics has moved on in many ways (I should have been more explicit about that myself), but the stuff that students are taught is still very much rooted in the old tradition. And these are people who graduate and then presumably go into business and politics believing that that is what economics is about – which is precisely my concern. This squares with what Robert Hunter Wade, a professor at LSE, says in his letter to the FT about how the simplistic picture of market efficiency is what tends to filter down to policy makers. All this leaves me thinking that it’s precisely for this reason that the simple picture of rational maximizers, equilibrium and market efficiency is perhaps a rather dangerous place to start from – sure, academic economists often (even generally) then move beyond it, but not everyone who draws on economic theory has learnt it beyond graduate level.

Much of the discussion prompted by my article has taken place in the blogs, however. Some of those I’ve spotted are here and here and here and here. A lot of the debate seems to focus on how stupid and misinformed my article was (although I can’t help thinking that there wouldn’t be quite so much discussion if it was that easy). I decided to take up the challenge on Dave Altig’s blog, which has been an instructive experience. At first I was taken aback by the aggression of the discourse, which was something I’ve just not experienced in the natural sciences. I don’t know if this is something specific to the economics world, or to the blogosphere generally, but it was not a pleasant discovery. However, I’m very grateful that Dave Altig has made some very gracious and polite comments that have cooled the tone and facilitated a far more constructive exchange. I was at fault here too, taking initially a more gung-ho tone than I needed to. (I think I was probably riled by some comments I received separately from an assistant professor at the University of Pennsylvania, which had a character I’d not experienced since the school playground.) It seems also that my FT piece was misread by some as being more insulting to economists than I’d intended – if that’s the impression I gave, then I regret it. I do think one sometimes needs to be provocative in order to spark a discussion, but I’d hoped to do that without seeming to jeer or ridicule.

I can’t possibly summarize all the blogging discussion; it’s there if you’re interested. But the discussion on Dave Altig’s site has been very useful for me, helping me to sharpen what it is I want to say while pointing to some issues that I need to go away and consider. His post of 9 November gives particularly valuable food for thought; thank you Dave.

Tuesday, November 07, 2006

When you can't do it all with mirrors[This is the unedited text of my recent article for muse@nature.com.]

A new proposal and costing for a technofix to global warming shows that there are probably better ways to spend the money

The leading economist Nicholas Stern has just handed us, in advance, the bill for the impacts of climate change: close to $4 trillion by the end of this century [1].

And with perfect timing, astronomer Roger Angel of the University of Arizona has delivered the equivalent of a builder's estimate for patching up the problem using a cosmic sunshade [2]. It will set us back by… well, let's make it a nice round figure of $4 trillion by the end of the century.

Both figures can be criticized – after all, when costs add up to a significant fraction of global GDP, no one can expect them to be very accurate. But this happy conflux of estimates puts some perspective on the hope that global warming can be addressed with high-tech mega-engineering projects.

From a pragmatic point of view, the sunshade solution looks like a bad bargain. If a builder told you that the cost of fixing a problem with your roof was likely to be about the same as the cost of not fixing it, except that the fix was untested and might not work at all, and in any event you know the work is likely to run over budget and probably over schedule – well, what would you do?

One could argue, however, that in this case the 'problem' involves the potential suffering of millions of people, who could be killed by disease or flood or drought, displaced from their homes, or caught up in conflict as a result of climate change – in which case you might conclude that investing in a risky technofix can be justified on humanitarian grounds.

But Stern's report, commissioned by the UK government and hailed by many other economists as the most definitive study of its sort to date, doesn't just tot up the costs of inaction over climate change. It makes some estimate of the likely costs of tackling it using existing approaches and technologies – and the answer looks cheaper and a whole lot more attainable than Angel's sunshade.

That doesn't mean Angel's proposal is without value. On the contrary, it performs the service of showing just what would be involved in pursuing one of the favourite ideas of those who believe technofixes could save us from rising world temperatures.

A space shade that reduces the amount of sunlight reaching the Earth has been debated for decades. Many of these schemes invoke a screen that would be unfolded or assembled in space, like a gigantic sail. But as James Early of the Lawrence Livermore National Laboratory in California pointed out in 1989 [3], a sail is precisely what it would be: radiation pressure would push against the sunshade, and it would therefore need to be kept actively in position.

Angel has found inventive ways of coping with all the challenges while keeping costs down. To minimize radiation pressure, the screen would deflect sunlight through only a small angle, just enough to miss the Earth. To keep it in line between the Earth and Sun, it would be placed at the so-called Lagrange point L1, a point in space 1.5 million km away that orbits the Sun with the same 1-year period as our planet.

The size of the screen would be mind-boggling: about 4-6 million square km, around half the area of China. But to avoid complicated space-assembly problems, and to simplify the launching and increase the screen's versatility, Angel proposes that it should consist of a vast swarm of 1-m disks, made from lightweight, microscopically perforated and laminated films of ceramics. Each of these 'flyers' is manoeuvrable thanks to tiny solar sails placed on tabs at the rim, powered by solar cells.

As usual, science fiction got there first. In a short story by Brenda Cooper and Larry Niven published in 2001, an alien species wipes out another by deploying a fleet of tiny mirrors around their planet, plunging it into an ice age [4] – a reminder, perhaps, that we'd better not overdo the shadowing.

Angel's flyers would be launched in stacks, like piles of Brobdingnagian dinner plates, packaged into canisters and fired into space from electromagnetic guns more than a kilometre long. Twenty such cannons would fire 1-ton payloads every five minutes for ten years. Once in space, the flyers make their way to the Lagrange point using fuel-efficient ion thrusters, where they spread out into a cloud as wide as the Earth and 100,000 km long.

And the bill, please? Estimating the costs of materials and launch facility, launch energy, and manufacturing, Angel says it could be done for less than $5 trillion.

All this sounds a long way from the sober accounting of the Stern report. But if you take the report seriously – and as a former chief economist of the World Bank, Stern apparently has the right credentials, although his conclusions have proved predictably controversial – it is similarly mind-boggling.

For example, Stern says that the impacts of climate change could end up costing the world up to 20% of its annual GDP. He compares the effect to that of the world wars or the Great Depression. The "radical change in the physical geography of the world" that climate change would produce, he says, "must lead to major changes in the human geography – where people live and how they live their lives".

Mitigating this potential crisis would require equally drastic measures. Stern does not consider technofixes like the space sunshade, but dwells instead on the far less sexy measure of reducing greenhouse-gas emissions. Gordon Brown, the UK's Chancellor of the Exchequer, who commissioned the report, has called for cuts of 30% by 2020 and 60% by 2050.

Stern's solutions involve energy-saving and improvements in energy efficiency, stopping deforestation, and switching to non-fossil-fuel energy sources. That will work only if the effort is international, he says (which is one reason why sceptics have scoffed), and it will incur a substantial cost: 1% of global GDP over the next 50 years, an amount that Stern calls "significant but manageable", and which squares with some previous estimates.

Whether the targets can be reached by putting solar cells on roofs, turning out lights, banning SUVs and building wind farms, or whether this will require more substantial measures such as new nuclear power stations, extensive carbon capture and sequestration, and fierce taxation of air travel, is a question that environmentalists, industrialists and politicians will continue to debate, no doubt as dogmatically as ever.

But as well as sketching an essay in ingenuity, Angel has done us the great favour of showing that there is probably never going to be the option of conducting business as usual under the shelter of a gigantic technofix.

Friday, November 03, 2006

I have drawn some inevitable flak for my criticisms of economic theory in the Financial Times. That’s no more than I expected. Here’s the article; the comments and my responses follow.

Baroque fantasies of a peculiar science

Published in the Financial Times, October 29 2006

It is easy to mock economic theory. Any fool can see that the world of neoclassical economics, which dominates the academic field today, is a gross caricature in which every trader or company acts in the same self-interested way – rational, cool, omniscient. The theory has not foreseen a single stock market crash and has evidently failed to make the world any fairer or more pleasant.

The usual defence is that you have to start somewhere. But mainstream economists no longer consider their core theory to be a “start”. The tenets are so firmly embedded that economists who think it is time to move beyond them are cold-shouldered. It is a rigid dogma. To challenge these ideas is to invite blank stares of incomprehension – you might as well be telling a physicist that gravity does not exist.

That is disturbing because these things matter. Neoclassical idiocies persuaded many economists that market forces would create a robust post-Soviet economy in Russia (corrupt gangster economies do not exist in neoclassical theory). Neoclassical ideas favouring unfettered market forces may determine whether Britain adopts the euro, how we run our schools, hospitals and welfare system. If mainstream economic theory is fundamentally flawed, we are no better than doctors diagnosing with astrology.

Neoclassical economics asserts two things. First, in a free market, competition establishes a price equilibrium that is perfectly efficient: demand equals supply and no resources are squandered. Second, in equilibrium no one can be made better off without making someone else worse off.

The conclusions are a snug fit with rightwing convictions. So it is tempting to infer that the dominance of neoclassical theory has political origins. But while it has justified many rightwing policies, the truth goes deeper. Economics arose in the 18th century in a climate of Newtonian mechanistic science, with its belief in forces in balance. And the foundations of neoclassical theory were laid when scientists were exploring the notion of thermodynamic equilibrium. Economics borrowed wrong ideas from physics, and is now reluctant to give them up.

This error does not make neoclassical economic theory simple. Far from it. It is one of the most mathematically complicated subjects among the “sciences”, as difficult as quantum physics. That is part of the problem: it is such an elaborate contrivance that there is too much at stake to abandon it.

It is almost impossible to talk about economics today without endorsing its myths. Take the business cycle: there is no business cycle in any meaningful sense. In every other scientific discipline, a cycle is something that repeats periodically. Yet there is no absolute evidence for periodicity in economic fluctuations. Prices sometimes rise and sometimes fall. That is not a cycle; it is noise. Yet talk of cycles has led economists to hallucinate all kinds of fictitious oscillations in economic markets. Meanwhile, the Nobel-winning neoclassical theory of the so-called business cycle “explains” it by blaming events outside the market. This salvages the precious idea of equilibrium, and thus of market efficiency. Analysts talk of market “corrections”, as though there is some ideal state that it is trying to attain. But in reality the market is intrinsically prone to leap and lurch.

One can go through economic theory systematically demolishing all the cherished principles that students learn: the Phillips curve relating unemployment and inflation, the efficient market hypothesis, even the classic X-shaped intersections of supply and demand curves. Paul Ormerod, author of The Death of Economics, argues that one of the most limiting assumptions of neoclassical theory is that agent behaviour is fixed: people in markets pursue a single goal regardless of what others do. The only way one person can influence another’s choices is via the indirect effect of trading on prices. Yet it is abundantly clear that herding – irrational, copycat buying and selling – provokes market fluctuations.

There are ways of dealing with the variety and irrationality of real agents in economic theory. But not in mainstream economics journals, because the models defy neoclassical assumptions.

There is no other “science” in such a peculiar state. A demonstrably false conceptual core is sustained by inertia alone. This core, “the Citadel”, remains impregnable while its adherents fashion an increasingly baroque fantasy. As Alan Kirman, a progressive economist, said: “No amount of attention to the walls will prevent the Citadel from being empty.”

So there you have it. Now the critics, published in the 1 November FT and online:

Letter 1:Did this sceptic ever take a course in the one science that calls itself dismal?

Sir, Philip Ball ("Baroque fantasies of a most peculiar science", October 30) quarrels with what he calls neoclassical economics. Perhaps his scarce argument may be better allocated against a competing end: might he notice that physics attempts to describe, explain and predict the action of matter in space, motion and time?

Economic theory establishes a baseline description of human behaviour, while always positing that when humans act, considerable complexity results. Perhaps Mr Ball never took a second course in the only science that, for its challenges, calls itself dismal.

Chris Robling, Chicago, IL 60602, US

Do you understand this? I don’t. Yes, that’s what physics does. And your point is?‘Economic theory establishes a baseline’: well yes, except that it doesn’t, because it manifestly doesn’t describe the way people act even to first order. But the real criticism is that neoclassical economics isn’t consistent even on its own terms – if you swallow its assumptions, the conclusions don’t follow. Steve Keen’s book Debunking Economics shows why.

“A second course”? Is this some kind of American euphemism? Sorry, too strange.

By the way, I suspect most people use the phrase ‘the dismal science’ without knowing what Carlyle was implying (or even that it was Carlyle who implied it). Look it up – it’s interesting. He considered economics dismal not because it was shoddy, but because it dealt with unpalatable truths about human nature. The article in which he used the phrase was, after all, about “the nigger question”.

Sir, Philip Ball says it is easy to mock economic theory ("Baroque fantasies of a most peculiar science", October 30). It is even easier to mock a caricature of economics, which is what he does, resorting to the tired cliché that we economists think we are doing mechanical physics. Once true, perhaps, but certainly not recently.

Like so many critics of economics, he paints an unrecognisable portrait of the subject. Economists do indeed use models that assume perfect competition and identical agents with unchanging behaviour, but only when it is useful to do so. At other times, we make other assumptions, including those used in the kind of models Mr Ball wrote about in his interesting book Critical Mass.

Economics is distinctive in using the concept of equilibrium - a state in which no individual consumer or business has an incentive to change behaviour - as a powerful analytical tool. It is so useful that evolutionary biologists, for example, use it all the time too.

I do of course have criticisms of my own subject. In particular, the typical undergraduate syllabus lags far behind all the remarkable developments of the past decade or two, such as information economics and behavioural economics. But the baroque citadel is Mr Ball's own fantasy; we economists moved out of it long ago, as a proper look at the mainstream journals (or a list of the Nobel winners) will show.

Diane Coyle, Enlightenment Economics, London W13 8PE, UK

Paul Ormerod tells me I would actually get on well with Diane. I think he’s right; I’ll probably get on with anyone who plugs my book. But I think I mostly agree with Diane anyway, except that I do wonder whether ‘we economists’ refers to a more select bunch than she appreciates. It is precisely those economist I mentioned in Critical Mass who are typically marginalized by the mainstream. I used ‘neoclassical’ so much in my article that I was worried by the repetition, precisely to make it clear that that is what I was criticizing, not the interesting ideas that get put forward outside of it. I understand that agent-based modelers have become so fed up with being excluded because their models violate neoclassical dogma that they have been forced to start their own journal. The ‘citadel’ is not my term, nor my fantasy – it is the expression used by Alan Kirman, one of the pioneers of economic agent-based approaches. Ask Paul Ormerod. Ask Paul Krugman, for that matter. If they all feel this way, surely there’s a reason?

Sir, I want to congratulate Philip Ball for his insightful and long-overdue comment about the domination of the economic profession by frustrated mathematicians and physics lecturers (October 30). He is incorrect in one regard, however, when he comments that "there is no other 'science' in such a peculiar state".

In fact, the worlds of finance and risk management have embraced the same nonsensical application of quantitative methods that he describes so well operating in the world of economics. This "derivative" view of credit risk and other important issues of global capital finance has badly damaged the ability of investors to perceive risk and gives managers an unreasonable view of the risks that they do accept. Witness the latest fiasco involving the hedge fund formerly called Amaranth. And there will be more examples very shortly.

Well, precisely. I talk briefly about derivatives and risk management in Critical Mass, simply to say that you’re not going to do very well forecasting risk if you insist on thinking that market noise is Gaussian.

Letter 4:Economists are busy dealing with the impact of 'real agents' in the economy

Sir, Contrary to what Philip Ball believes, many economists are already busy "dealing with the variety and irrationality of real agents" ("Baroque fantasies of a most peculiar science", October 30). These economists include several Nobel prize-winners: Herbert A. Simon, Daniel Kahneman, Vernon L. Smith and Thomas C. Schelling. In fact, the Nobel prize this year was awarded to Edmund Phelps for challenging the Phillips curve trade-offs by "taking into account problems of information in the economy".

Mocking economic theory is easy but doing so by perpetuating "rigid dogma" about economics and economists is pure hearsay. A survey of recent literature in mainstream economic journals or textbooks should enlighten this misconceived view.

Chee Kian Leong, 639798 Singapore

OK, so it’s basically the same point as Diane Coyle’s. But the question of the Nobels is curious. (Needless to say, Simon and Schelling loom large in Critical Mass.) I’ve talked with others about the strange fact that economics Nobels often (though by no means always) go to contributions that lie outside the mainstream, and thus outside of neoclassical dogma. (One could add Stiglitz and Sen to the list, for example.) This speaks of impeccable taste (or nearly so) on the part of the Nobel committee. But it is puzzling – nothing like it happens in the other ‘sciences’.

The bottom line is: do you believe in neoclassical general equilibrium theory, with its efficient market hypothesis, its exogenous shocks, its aggregate price curves and all the rest? If not, do you think it is right that this is what students learn and come to believe about the way the economy works? And that papers which question the theory’s fundamental principles should be excluded from much of the literature?

Wednesday, October 25, 2006

In defence of consensus

If I were to hope for psychological subtlety from soap operas, or historical accuracy from Dan Brown, I’d have only myself to blame for my pain. So I realize that I am scarcely doing myself any favours by allowing myself to be distressed by scientifically illiterate junk in the financial pages of the Daily Telegraph. I know that. Yet there is a small part of me, no doubt immature, that exclaims “But this is a national newspaper – how can it be printing sheer nonsense?”

To wit: Ruth Lea, director of the Centre for Policy Research, on the unreliability of consensus views. These are, apparently, “frequently very wrong indeed.” The target of this extraordinarily silly diatribe is the consensus on the human role in climate change. We are reminded by Lea that Galileo opposed the ‘consensus’ view. Let’s just note in passing that the invocation of Galileo is the surefire signature of the crank, and move on instead to the blindingly obvious point that Galileo’s ‘heresy’ represented the voice of scientific reason, and the consensus he opposed was a politico-religious defence of vested interests. Rather precisely, one might think, the opposite of the situation in the climate-change ‘consensus.’ (The truth about Galileo is actually a little more complicated – see Galileo in Rome by William Shea and Mariano Artigas – but this will do for now.)

In any case, the rejoinder is really very simple. Of course scientific consensus can be wrong – that’s the nature of science. But much more often it is ‘right’ (which is to say, it furnishes the best explanation for the observations with the tools to hand).

As further evidence of the untrustworthiness of consensus, however, Lea regales us with tales of how economists (for God’s sake) have in the past got things wrong en masse – apparently she thinks economics has a claim to the analytical and predictive capacity of natural science. Or perhaps she imagines that consensus-making is an arbitrary affair, a thing that just happens when lots of people get together to debate an issue, and not, as in science, a hard-won conclusion wrested from observation and understanding.

Ah, but you see, the science of global warming has been overturned by a paper “of the utmost scientific significance”, published by the venerable Royal Society. The paper’s author, a Danish scientist named Henrik Svensmark, “has been impeded and persecuted by scientific and government establishments” (they do that, you know) because his findings were “politically inconvenient”. What are these findings of the “utmost significance”? He has shown, according to Lea, that there has been a reduction in low-altitude cloudiness in the twentieth century owing to a reduction in the cosmic-ray flux into the atmosphere, because of a weakening of the shielding provided by the Sun’s magnetic field. Clouds have an overall cooling effect, and so this reduction in cloudiness probably lies behind the rise in global mean temperature.

Now, that sounds important, doesn’t it? Except that of course Svensmark has shown nothing of the sort. He has found that cosmic rays may induce the formation of sulphate droplets in a plastic box containing gases simulating the composition of the atmosphere. That’s an interesting result, demonstrating that cosmic rays might indeed affect cloud formation. It’s certainly worth publishing in the Proceedings of the Royal Society. The next step might be to look for ways of investigating whether the process works in the real atmosphere (and not just a rough lab simulacra of it). And then whether it does indeed lead to the creation of cloud condensation nuclei (which these sulphate droplets are not yet), and then to clouds. And then to establish whether there is in fact any record of increased cosmic-ray flux over the twentieth century. (We can answer that already: it’s been measured for the past 50 years, and there is no such trend.) And then whether there is evidence of changes in low-altitude cloudiness of the sort Svensmark’s idea predicts. And if so, whether it leads to the right predictions of temperature trends in climate models. And then to try to understand why the theory predicts a stronger daytime warming trend, whereas observations show that it’s stronger at night.

But that’s all nitpicking, surely, because in Lea’s view this new result “seriously challenges the current pseudo-consensus that global warming is largely caused by manmade carbon emissions.” Like most climate-change sceptics, Lea clearly feels this consensus is pulled out of a hat through vague and handwaving arguments, rather than being supported by painstaking comparisons of modelling and observation, such as the identification of a characteristic anthropogenic spatial fingerprint in the overall warming trend. It is truly pitiful.

“I am no climate scientist”, says Lea. (I take it we could leave out “climate” here.) So why is she commenting on climate science? I am no ballet dancer, which is why, should the opportunity bizarrely present itself for me to unveil my interpretation of Swan Lake before the nation, I will regretfully decline.

Simon Jenkins has recently argued in the Guardian that science should not be compulsory beyond primary-school level. I don’t think we need be too reactionary about his comments, though I disagree with much of them. But when a director of a ‘policy research centre’ shows such astonishing ignorance of scientific thinking, and perhaps worse still, no one on a national newspaper’s editorial or production team can see that this is so (would the equivalent historical ignorance be tolerated, say?), one has to wonder whether increasing scientific illiteracy still further is the right way to go. In fact, the scientific ignorance on display here is only the tip of the iceberg. The real fault is a complete lack of critical thinking. There are few things more dangerous in public life than people educated just far enough to be able to mask that lack with superficially confident and polished words.

But it’s perhaps most surprising of all to see someone in ‘policy research’ fail to understand how a government should use expert opinion. If there is a scientific consensus on this question, what does she want them to do? The opposite? Nothing? A responsible government acts according to the best advice available. If that advice turns out to be wrong (and science, unlike politics, must always admit to that possibility), the government nevertheless did the right thing. If this Policy Research Centre actually has any influence on policy-making, God help us.

Monday, October 23, 2006

Decoding Da Vinci, decoded

I’m hoping that anyone who feels moved to challenge my dismissal of Fibonacci sequences and the Golden Mean in nature, in the Channel 4 TV series Decoding da Vinci will think first about how much ends up on the cutting-room floor in television studios. I stand by what I said in the programme, but I didn’t suggest to the presenter Dan Rivers that Fibonacci and phi are totally irrelevant in the natural world. Sure, overblown claims are made for them – just about all of what is said in this regard about human proportion is mere numerology (of which my favourite is the claim that the vital statistics of Veronica Lake were Fibonacci numbers). And the role of these numbers in phyllotaxis has been convincingly challenged recently by Todd Cooke, in a paper in the Botanical Journal of the Linnean Society. But even Cooke acknowledges that the spiral patterns of pine cones, sunflower florets and pineapples do seem to have Fibonacci parastichies (that is, counter-rotating spirals come in groups of (3,5), (5,8), (8,13) and so on). That has yet to be fully explained, although it doesn’t seem to be a huge mystery: the explanation surely has something to do with packing effects at the tip of the stem, where new buds form. It’s a little known fact that Alan Turing was developing his reaction-diffusion theory of pattern formation to explain this aspect of phyllotaxis just before he committed suicide. Jonathan Swinton has unearthed some fascinating material on this.

So the real story of Fibonacci numbers and phi in phyllotaxis is complicated, and certainly not something that could be squeezed into five minutes of TV. I shall discuss it in depth in my forthcoming, thorough revision of my book The Self-Made Tapestry, which Oxford University Press will publish as a three volume-set (under a title yet to be determined), beginning some time in late 2007.

Thursday, October 19, 2006

I don’t generally tend to post my article for Nature’s nanozone here, as they are a bit too techie. But this was just such a cute story…

Nanotechnology is older than we thought. The Egyptians were using it four millennia ago to darken their graying locks.

Artisans were making semiconductor quantum dots more than four thousand years ago, a team in France has claimed. Needless to say, the motivation was far removed from that today, when these nanoparticles are of interest for making light-emitting devices and as components of photonic circuits and memories. It seems that the ancient Egyptians and Greeks were instead making nanocrystals to dye their hair black.

Philippe Walter of the Centre for Research and Restoration of the Museums of France in Paris and his colleagues have investigated an ancient recipe for blackening hair using lead compounds. They find that the procedure described in historical sources produces nanoparticles of black lead sulphide (PbS), which are formed deep within the protein-rich matrix of hair [1].

That the chemical technologies of long ago sometimes involved surprisingly sophisticated processes and products is well known [2]. The synthesis of nanoparticles has, for example, been identified in metallic, lustrous glazes used by potters in the Middle Ages [3]. Such practices are remarkable given that ancient craftspeople generally had no real knowledge of chemical principles and had only crude means of transforming natural materials, such as heating, at their disposal.

The nanocrystal hair dye is particularly striking. Walter and colleagues say that these particles, with a size of about 5 nm, are “quite similar to PbS quantum dots synthesized by recent materials science techniques.” Moreover, the method alters the appearance of hair permanently, because of the deep penetration of the nanoparticles, yet without affecting its mechanical properties.

That makes the process an attractive dyeing procedure even today, despite the potential toxicity of lead-based compounds. Walter and colleagues point out that some modern hair darkeners indeed contain lead acetate, which forms lead sulphide in situ on hair fibres. In any event, safety concerns do not seem to have troubled people in ancient times, perhaps because of their short life expectancy – as well as using lead to dye hair, the Egyptians used lead carbonate as a skin whitener, and toxic antimony sulphide for eye shadow (kohl).

The recipe for making the lead-based hair dye is simple. Lead oxide is mixed with slaked lime (calcium hydroxide, which is strongly alkaline) and water to make a paste, which is then rubbed into the hair. A reaction between the leads ions and sulphur from hair keratins (proteins) produces lead sulphide. These proteins have a high sulphur content: they are strongly crosslinked by disulphide bonds formed from cysteine amino acids, which gives hair its resilience and springiness (such bonds are broken in hair-straightening treatments). The researchers found that the alkali seems to be essential for releasing sulphur from cysteine to form PbS.

The French team dyed blond human hairs black by applying this treatment for three days. They then looked at the distribution of lead within cross-sections of the hairs using X-ray fluorescence spectroscopy, and saw that it was present throughout. X-ray diffraction from treated hairs showed evidence of lead sulphide crystals, which electron microscopy revealed as nanoparticles about 4.8 nm across.

The nanoparticles decorate fibrillar aggregates of proteins within the cortex of hair strands – the inner region, beneath the cuticle of the hair surface. High-resolution microscopy revealed that these particles are highly organized: they seem to be attached to individual microfibrils, which are about 7 nm in diameter and are formed from alpha-helical proteins. Thus the distribution of particles echoes the supramolecular arrangement of the microfibrils, being placed in rows about 8-10 nm apart and aligned with the long axis of the hair strands. So the ancient recipe provides a means not only of making nanocrystals but of organizing them in a roughly regular fashion at the nanoscale – one of the major objectives of modern synthetic methods.

The discovery throws a slightly ironic light on the debate today about the use of nanoparticles in cosmetics [4]. Quite properly, critics point out that the toxicological behaviour of such particles is not yet well understood. It now seems this is a much older issue than anyone suspected.

Tuesday, October 17, 2006

A sign of the times?

The ETC Group, erstwhile campaigners against nanotechnology, have launched a competition for the design of a ‘nano-hazard’ symbol analogous to those used already to denote toxicity, biohazards or radioactive materials. My commentary for Nature’s muse@nature.com on this unhelpful initiative is here.

I worry slightly that the ETC Group is a soft target, in that their pronouncements on nanotechnology rarely make much sense and show a deep lack of understanding of the field (and I say this as a supporter of many environmental causes and a strong believer in the ethical responsibilities of scientists). But I admit that the announcement left me a little riled, filled as it was with a fair degree of silliness and misinformation. For example:

“Nanoparticles are able to move around the body and the environment more readily than larger particles of pollution.” First, we don’t know much about how nanoparticles move around the body or the environment (and yes, that’s a problem in itself). Second, this sentence implies that nanoparticles (here meaning human-made nanoparticles, though that’s not specified) are ‘pollution’ by default, which one simply cannot claim with such generality. Some may be entirely harmless.

“Some designer nanomaterials may come to replace natural products such as cotton, rubber and metals – displacing the livelihoods of some of the poorest and most vulnerable people in the world.” I don’t want to see the livelihoods of poor, vulnerable people threatened. Yet not only is this claim completely contentious, but it offers us the prospect of a group that originated from concerns about soil erosion and land use now suggesting that metals are ‘natural products’ – as though mining has not, since ancient times, been one of the biggest polluters on the planet.

“Nano-enabled technologies also aim to ‘enhance’ human beings and ‘fix’ the disabled, a goal that raises troubling ethical issues and the specter of a new divide between the technologically “improved” and “unimproved.”” Many of these ‘human enhancements’ are silly dreams of Californian fantasists. There’s nothing specific to nanotech in such goals anyway. What nanotech does show some promise of doing is enabling important advances in biomedicine. If that is a ‘fix’, I suspect it is one many people would welcome.

And so on. I was one of those who wrote to the Royal Society, when they were preparing their report on nanotech, urging that they take seriously the social and ethical implications, even if these lay outside the usual remit of what scientists consider in terms of ethics. I feel that is an important obligation, and I was glad to see that the Royal Society/RAE report acknowledges it as such. But sticking ‘Danger: Nano’ stickers on sun creams isn’t the answer.

Friday, October 06, 2006

[The following is the unedited form of my latest article on muse@nature.com. The newsblog on this story is worth checking out too.]

By confronting ExxonMobil, the Royal Society is not being a censor of science but an advocate for it.

When Bob Ward, former manager of policy communication at the Royal Society in London, wrote a letter to the oil company ExxonMobil taking it to task for funding groups that deny the human role in global warning, it isn’t clear he knew quite what he was letting himself in for. But with hindsight the result was predictable: once the letter was obtained and published by the British Guardian newspaper, the Royal Society (RS) was denounced from all quarters as having overstepped its role as impartial custodians of science.

Inevitably, Ward’s letter fuels the claims of ‘climate sceptics’ that the scientific community is seeking to impose a consensus and to suppress dissent. But the RS has been denounced by less partisan voices too. David Whitehouse, formerly a science reporter for the BBC, argues that “you tackle bad science with good science”, rather than trying to turn off the money to your opponents. “Is it appropriate”, says Whitehouse, “that [the RS] should be using its authority to judge and censor in this way?”

And Roger Pielke Jr, director of the University of Colorado’s Center for Science and Technology Policy Research, who is a controversialist but far from a climate sceptic, says that “the actions by the Royal Society are inconsistent with the open and free exchange of ideas, as well as the democratic notion of free speech.”

Yes, there is nothing like the scent of scientific censorship to make scientists of all persuasions come over all sanctimonious about free speech.

The problem is that these critics do not seem to understand what the RS (or rather, Bob Ward) actually said, nor the context in which he said it, nor what the RS now stands for.

Ward wrote his letter to Nick Thomas, Director of Corporate Affairs at ExxonMobil’s UK branch Esso. He expressed surprise and disappointment at the way that ExxonMobil’s 2005 Corporate Citizenship Report claimed that the conclusions of the Intergovernmental Panel on Climate Change that recent global warming has a human cause “rely on expert judgement rather than objective, reproducible statistical methods”. Ward’s suggestion that this claim is “inaccurate” is in fact far too polite.

Model uncertainties and natural variability, the report goes on to claim, “make it very difficult to determine objectively the extent to which recent climate changes might be the result of human actions.” But anyone who has followed the course of the scientific debate over the past two decades will know how determinedly the scientists have refrained from pointing the finger at human activities until the evidence allows no reasonable alternative.

Most serious scientists will agree on this much, at least. The crux of the argument, however, is Ward’s alleged insistence that ExxonMobil stop funding climate-change deniers. (He estimates that ExxonMobil provided $2.9 million last year to US organizations “which misinformed the public about climate change.”) Actually, Ward makes no such demand. He points out that he expressed concerns about the company’s support for such lobby groups in a previous meeting with Thomas, who told him that the company intended to stop it. Ward asked in his letter when ExxonMobil plans to make that change.

So there is no demand here, merely a request for information about an action ExxonMobil had said it planned to undertake. Whitehouse and Pielke are simply wrong in what they allege. But was the RS wrong to intervene at all?

First, anyone who is surprised simply hasn’t being paying attention. Under outspoken presidents such as Robert May and Martin Rees, the Royal Society is no longer the remote, patrician and blandly noncommittal body of yore. It means business. In his 2005 Anniversary Address, May criticized “the campaigns waged by those whose belief systems or commercial interests impel them to deny, or even misrepresent, the scientific facts”.

“We must of course recognise there is always a case for hearing alternative, even maverick, views”, he added. “But we need to give sensible calibration to them. The intention of ‘balance’ is admittedly admirable, but this problem of wildly disparate ‘sides’ being presented as if they were two evenly balanced sporting teams is endemic to radio, TV, print media, and even occasional Parliamentary Select Committees.”

In response to his critics, Ward has said that “the Society has spoken out frequently, on many issues and throughout its history, when the scientific evidence is being ignored or misrepresented”. If anything, it hasn’t done that often enough.

Second, Ward rightly ridicules the notion of ExxonMobil as the frail David to the Royal Society’s Goliath. The accusations of “bullying” here are just risible. The RS is no imperious monarch, but a cash-strapped aristocrat who lives in the crumbling family pile and contrives elegantly to hide his impecuniosity. In contrast, the climate sceptics count among their number the most powerful man in the world, who has succeeded in emasculating the only international emissions treaty we have.

And it’s not just the oil industry (and its political allies) that the RS faces. The media are dominated by scientific illiterates like Neil Collins, who writes in the Telegraph newspaper à propos this little spat of his “instinctive leaning towards individuals on the fringe”, that being the habitual raffish pose of the literati. (My instinctive leaning, in contrast, is towards individuals who I think are right.) “Sea level does not appear to be rising”, says Collins (wrong), while “the livelihoods of thousands of scientists depend on our being sufficiently spooked to keep funding the research” (don’t even get me started on this recurrent idiocy). I fear the scientific community does not appreciate the real dangers posed by this kind of expensively educated posturing from high places.

If not, it ought to. In the early 1990s, the then editor of the Sunday Times Andrew Neil supported a campaign by his reporter Neville Hodgkinson suggesting that HIV does not cause AIDS.

Like most climate sceptics, Neil and the HIV-deniers did not truly care about having a scientific debate – their agenda was different. To them, the awful thing about the HIV theory was that it placed every sexual libertine at risk. How dare science threaten to spoil our fun? Far better to confine the danger to homosexuals: Hodgkinson implied that AIDS might somehow be the result of gay sex. For a time, the Sunday Times campaign did real damage to AIDS prevention in Africa. But now it is forgotten and the sceptics discredited, while Neil has gone from strength to strength as a media star.

On that occasion, Nature invited accusations of scientific censorship by standing up to the Sunday Times’s programme of misinformation – making me proud to be working for the journal. As I recall, the RS remained aloof from that matter (though May mentions it in his 2005 speech). We should be glad that it is now apparently ready to enter the fray. Challenging powerful groups that distort science for personal, political or commercial reasons is not censorship, it is being an advocate for science in the real world.